Clinical diagnostic value of simultaneous amplification and testing for the diagnosis of sputum-scarce pulmonary tuberculosis

• Published in: BMC infectious diseases Vol. 17; no. 1; p. 545
• Main Authors: Yan, Liping, Zhang, Qing, Xiao, Heping
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 05.08.2017; BioMed Central; BMC
• Subjects: Acids; Alveoli; Amplification; Assaying; Bacteriological Techniques - methods; BALF; Biological assay; Bronchoalveolar Lavage Fluid - microbiology; Care and treatment; Case-Control Studies; Computed tomography; Culture; Culture test; Diagnosis; Diagnostic systems; Humans; Infectious diseases; Innovations; Laboratories; Medical imaging; Methods; Microbiology; Molecular diagnostic techniques; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - pathogenicity; Nucleic Acid Amplification Techniques - methods; Patients; Prospective Studies; Pulmonary tuberculosis; SAT-TB assay; Sensitivity; Sensitivity and Specificity; Smear; Smear test; Sputum; Sputum - microbiology; Test procedures; Tomography; Tomography, X-Ray Computed; Tuberculosis; Tuberculosis, Pulmonary - diagnosis; Tuberculosis, Pulmonary - diagnostic imaging; China; Culture test; Smear test; SAT-TB assay; BALF; Pulmonary tuberculosis
• ISSN: 1471-2334; 1471-2334
• DOI: 10.1186/s12879-017-2647-7

Since 20% of pulmonary tuberculosis (PTB) patients are asymptomatic, the early detection of PTB is a challenge particularly in sputum-scarce patients and diagnostic accuracy based solely on clinical characteristics and chest X-ray/CT scans are not always satisfactory. The AmpSure simultaneous amplification and testing method for the detection of Mycobacterium tuberculosis (SAT-TB assay) is an alternative approach to diagnose PTB. In the present study, we analyzed the usefulness of the SAT-TB assay for PTB diagnosis in sputum-scarce patients. A total of 840 patients were prospectively enrolled for PTB diagnosis with bronchial alveolar lavage fluid (BALF) used as the samples for the SAT-TB assay. Of these, 536 had a definite diagnosis of PTB confirmed by positive microbiology culture, or clinical diagnosis of active PTB following anti-TB treatment with a favorable response. The SAT-TB assay showed a 76.44% agreement with the culture test. The sensitivity and specificity of the SAT-TB assay were 50.75% and 94.73%, respectively. The sensitivity of SAT-TB was significantly higher than that of BALF cultures (21.64%) (X  = 49.1503; P < 0.001) and smears (4.48%) (X  = 175.2315; P < 0.001). The specificity of SAT-TB was slightly lower than that of BALF cultures (98.25%) (X  = 2.0727; P = 0.150) and smears (98.25%) (X  = 2.0727; P = 0.150). The accuracy rates were 63.87% for SAT-TB, 44.50% for BALF cultures and 29.84% for BALF smears. The high accuracy of the SAT-TB assay indicated that active PTB is present and anti-TB treatment is strongly recommended regardless of smear and culture test results for sputum scarce active PTB suspected patients when BALF SAT-TB is positive.